Abstract: The extraction of total flavonoids from the aboveground parts of Kalimeris indica L. wildly grown in Huaguoshan Mountain, Lianyungang was optimized. Based on one-factor-at-a-time experiments, a 4-variable, 3-level central composite design was carried out to establish a quadratic regression model for the extraction efficiency of total flavonoids as a function of temperature, time, liquid-to-solid ratio and ethanol concentration. The model was analyzed by response surface methodology to find optimal conditions for the extraction of total flavonoids. The highest extraction efficiency of total flavonoids, of which the  predicted and experimental values were 1.65% and 1.62%, respectively, was achieved after 105 min of extraction at 71 ℃ using 63% aqueous ethanol as the extraction solvent at a liquid-to-solid ratio of 26.5:1 (mL/g).

Key words: Kalimeris indica L., total flavonoids, extraction, response surface methodology (RSM)